JPH0754605Y2 - Silencer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a muffler mounted on an intake / exhaust air duct of an automobile engine or the like.

It is theoretically known that it is effective to reduce the inner volume by reducing the cross-sectional area of the air duct in order to reduce the intake noise of the intake air duct, especially in the intake and exhaust air ducts. Has been. However, reducing the cross-sectional area is problematic because the resistance of the intake air increases. In particular, considering the influence in the high-speed rotation region of the engine, there is a limit in reducing the cross-sectional area of the intake air duct.

In this regard, the air duct itself has a required cross-sectional area, and by branching the resonance box from the air duct,
A structure in which the resonance frequency is resonantly attenuated by this resonance box is well known. That is, in the case of a Helmholtz type silencer in which the resonance box is branched to the outside of the air duct, it silences noise in a specific low frequency region, for example, reduces muffled sound in the vehicle compartment, or aims to prevent noise leakage to the outside of the vehicle. Used.

Generally, the muffled sound in the vehicle interior is a phenomenon in which when the engine reaches a specific rotation speed, the sound pressure increases due to resonance with the air vibration system including the volume of the vehicle interior. It is known that the frequency region in which the muffled sound is generated is not limited to one engine rotation speed region but is generated in a plurality of rotation speed regions. Therefore, it is necessary to set a plurality of resonance regions in order to attenuate muffled sound in a plurality of rotation speed regions.

Normally, for the attenuation of one noise frequency, only one resonator with the corresponding internal volume is effective. Therefore, in order to set a plurality of resonance regions, it is necessary to branch a plurality of resonance boxes having the corresponding internal volumes from the air duct. As a result, a plurality of muffled noises generated in a wide range of engine speed can be attenuated and reduced.

Problems to be Solved by the Invention By the way, there is a fundamental problem in that a structure in which a single or a plurality of resonance boxes are projected outside the air duct itself requires a large mounting space. In addition to this, installing a plurality of resonators as described above not only increases the cost but also increases the weight and bulk volume, and requires a large mounting space. There is also a problem that affects the layout of the interference problem.

An object of the present invention is to provide a silencer that requires a minimum of mounting space and can handle noise in a wide range of engine rotation.

Means for Solving the Problems A muffler according to the present invention includes an air duct for an intake system or an exhaust system, a partition wall that divides the inside of the air duct into two passages extending in the axial direction, and branches from the air duct through a communication port. A resonance box portion communicating with one passage in the air duct, and an opening / closing valve rotatably supported by an upstream opening of the one passage to close or open the upstream opening, the opening / closing valve being upstream of the one passage. The contact opening is closed from the closed position of the mouth to close the communication opening, and the connection opening is further opened from the closed position to open the communication opening.

The internal volume of the air duct is changed by the opening / closing operation of the opening / closing valve corresponding to the engine speed. When the flow rate of intake air or exhaust gas is low at low speed rotation, one of the two passages in the air duct is closed by the on-off valve.
At this time, noise such as muffled sound due to the low-speed rotation frequency is resonated in the resonance box portion to be attenuated and reduced.

When a large amount of intake air or exhaust air is required at the time of high speed rotation, all two passages in the air duct are opened, and the opening / closing valve closes and closes the resonance box portion.

Also, open all two passages in the air duct,
Moreover, when the on-off valve is operated in the direction to open the resonance box part, a large amount of intake air or exhaust gas can be circulated, and the damping frequency can be set high by opening the resonance box part.

Embodiment Hereinafter, an embodiment of the silencer according to the present invention will be described with reference to the drawings.

1 to 3 show an intake air duct 10 which is connected to, for example, a suction port of a carburetor of an engine. Inside the air duct 10 close to the upstream end 11, a partition 12 is formed extending in the longitudinal axis direction, and the partition 12 forms an air duct.
The inside of 10 is divided into two upper and lower passages 10A and 10B. The opening / closing valve 13 is rotatably supported by the inlet 12a on the upstream side of the lower passage 10B via a support pin 14, and the passage 10B is closed or opened on the inlet side by the operation of the opening / closing valve 13. That is,
When the on-off valve 13 is closed and the passage 10B is shut off, the air duct 1
The inside of 0 is only the upper passage 10A, and when the opening / closing valve 13 is opened, the inside of the air duct 10 forms a flow passage in which the cross sections of the upper and lower passages 10A and 10B are combined.

Further, at a position adjacent to the opening / closing valve 13 and facing the lower passage 10B, a communication port 15 that opens the peripheral wall of the air duct 10 is provided, and the resonance box part 16 is connected to the air duct through the communication port 15.
It branches from 10. The on-off valve 13 can also open and close the communication port 15, and when the communication port 15 is opened, the resonance box part 16 having the internal volume 17 can communicate with the lower passage 10B in the air duct 10. It has become.

Here, the opening / closing operation of the on-off valve 12 is performed by an actuator that operates according to a control signal from the control device. For example, when the control is performed based on the electric signal of the engine speed N (rpm), the engine speed is detected by the rotation sensor, and this detection signal is sent to the control device. The control device performs control based on the detection signal and outputs the signal to the actuator. As the actuator, there are an electric actuation type such as an electromagnetic solenoid and an intake negative pressure type.

Next, the operation mode and operation of this embodiment will be described. Here, it is assumed that the air duct 10 is an intake system.

The amount of intake air is small during operation when the engine speed is low. In this case, as shown in FIG. 1, no signal is sent from the control device and the actuator does not operate, so the on-off valve 12 is in the closed state. That is, inside the air duct 10, the lower passage 10A is closed by the upstream inlet 12a by the partition wall 12, so that the intake air flows in the air duct 10 only through the upper passage 10A. In this case, the passage 10b constitutes a resonance part together with the resonance box part 16. Therefore, it is particularly effective in attenuating low frequency noise, and the muffled sound in the vehicle interior can be reduced.

Further, when the intake air amount is increased during the operation at the high engine speed, the opening / closing valve 12 is opened and the passage 10B is opened as shown in FIG. That is, a signal from the control device is sent to the actuator, and the opening / closing valve 13 is rotated in the direction to open the passage 10B via the spindle pin 14 by the operation of the actuator. At the same time, the opening / closing valve 13 closes the communication port 15 leading to the resonance box portion 16. As a result, the intake resistance inside the air duct 10 is reduced, and a large amount of intake air flows through both upper and lower passages 10A, 10B.

Further, as shown in FIG. 3, the opening / closing valve 13 with the communication port 15 closed is further rotated from this position to enter the resonance box portion 16 side, and the communication port 15 is opened. In this case, the intake resistance is reduced by opening the two passages 10A and 10B as in the case of the high speed engine rotation of FIG. 2, so that a large amount of intake air can be distributed. Further, by opening the communication port 15, the inside of the air duct 10 communicates with the inside of the resonance box portion 16. As a result, the attenuation frequency can be set to a higher frequency than in the case of FIG.

On the other hand, FIGS. 4 and 5 show two other embodiments of the present invention, both of which are side-branch silencers. That is, as in the case of the first embodiment shown in FIG. 1 to FIG.
The main point is that the two passages 10A and 10B are configured. As shown in the figure, the on-off valve 13 is closed and the one passage 10B is configured as a side branch type resonance box portion.

Effect of the Invention As described above, in the muffler according to the present invention, a part of the structure of the muffler is included inside the air duct, so that the mounting space can be significantly reduced. Further, there is an advantage that the noise can be silenced corresponding to the respective noise frequencies at low engine speed and high engine speed, and for example, intake resistance can be reduced at high engine speed.

[Brief description of drawings]

1 to 3 are cross-sectional views of an embodiment of a silencer according to the present invention, FIG. 1 is a cross-sectional view of the engine at high speed rotation, FIG. 2 is a cross-sectional view of the engine at low speed rotation, FIG. 3 is a sectional view of the mode at the time of high speed rotation. Also, FIGS. 4 and 5 show sectional views of two other embodiments. 10 …… air duct, 12 …… bulkhead, 13 …… open / close valve, 15 ……
Contact port, 16 ... Resonance box

Claims (1)

[Scope of utility model registration request] 1. An air duct for an intake system or an exhaust system, a partition wall that divides the interior of the air duct into two passages extending in the axial direction, and a resonance that branches from the air duct through a communication port and communicates with one passage in the air duct. It includes a box part and an opening / closing valve that is rotatably supported by the upstream opening of one of the passages to close or open the upstream opening, and the opening / closing valve turns in a direction of opening from the position where the upstream opening of the one passage is closed. A muffler that is configured to operate to close the communication port, and then perform a further rolling operation from this closed position to open the communication port.